Laser Cut Joint Formation to Prevent Melt Blow-Up
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Solution Overview
Problem
Conventional laser machining techniques face challenges in forming a desired shape for coupling pieces due to increased cutting speed and reduced laser output, leading to potential melt blow-up and machining defects.
Innovation Solution
A laser machining apparatus that controls the irradiation of a workpiece with a pulsed laser beam and machining gas, including a first waiting time to ensure complete melt discharge and a second pulse condition for forming a joint portion with reduced thermal energy, to precisely create a coupling piece with a desired shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting speed is increased and the laser output is reduced, then the productivity is improved, but the manufacturing precision deteriorates due to inability to obtain a coupling piece with desired shape
Solution Approach 1:
The patent applies periodic action by using pulsed laser irradiation instead of continuous irradiation. The laser beam is irradiated in pulses with specific pulse widths and intervals, allowing controlled melting and discharge cycles that prevent melt blow-up while maintaining cutting speed. This periodic irradiation pattern enables precise control over the coupling piece formation process.
Solution Approach 2:
The patent implements dynamics by making the laser irradiation conditions adjustable and variable. The control unit dynamically adjusts laser output, pulse width, and irradiation intervals based on real-time machining state. This dynamic control allows optimization of both cutting speed and coupling piece shape precision under different machining conditions.
2Productivity
If the cutting speed is increased, then the productivity is improved, but the manufacturing precision deteriorates due to melt blow-up covering the product
Solution Approach 1:
The patent employs feedback control by using a detection unit to monitor the machining state in real-time and adjusting laser irradiation conditions accordingly. The control unit receives detection signals and modifies laser output, pulse width, or irradiation intervals to prevent melt blow-up that would cover the product. This closed-loop control ensures high surface quality while maintaining productivity.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting laser irradiation parameters (output, pulse width, frequency, duty cycle) based on machining conditions. These parameter modifications control the melting and discharge rates, preventing melt blow-up at high cutting speeds while maintaining product surface quality and coupling piece precision.
3Manufacturing precision
If the laser output is reduced, then the manufacturing precision is improved for coupling piece shape, but the productivity deteriorates due to slower cutting speed
Solution Approach 1:
The patent resolves this contradiction by using periodic pulsed irradiation with optimized pulse widths and intervals. This allows the laser to deliver sufficient energy for precise coupling piece formation during pulse periods while allowing cooling and discharge during interval periods, thereby maintaining both precision and acceptable cutting speed.
Solution Approach 2:
The patent applies preliminary anti-action by stopping irradiation before the laser beam reaches the endpoint position, and continuing gas ejection for a predetermined waiting time. This preliminary action prevents melt from being blown up to cover the product while ensuring complete discharge of molten material, thereby maintaining precision without excessive reduction in cutting speed.
4Manufacturing precision
If the irradiation is stopped before reaching the endpoint, then the manufacturing precision is improved by preventing melt blow-up, but the productivity deteriorates due to waiting time
Solution Approach 1:
The patent applies partial action by stopping irradiation at a position short of the endpoint and using gas ejection alone to complete the discharge process. This partial laser action prevents melt blow-up while the continued gas flow finishes clearing the molten material, achieving precision with minimized waiting time compared to complete irradiation stoppage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus reliably forms a coupling piece with a desired shape, preventing melt blow-up and ensuring accurate cutting, thus improving the quality of the machining process.
Implementation Method 1
irradiating a workpiece with a laser beam
Implementation Method 2
the workpiece positioned above the coupling piece is certainly melted
Implementation Method 3
ejecting gas to the workpiece
Data Source
AI summary
A control unit performs: a control of forming a cut groove by running a first laser beam along a machining path in an in-plane direction of an upper surface of the workpiece; a control of stopping irradiation with the first laser beam when an irradiation position of the laser beam reaches a position short of an end point on the machining path; and a control of continuing ejection of gas over a first waiting time. The control unit performs: a control of irradiating the workpiece with a second laser beam that gives less thermal energy to the workpiece per unit time than the first laser beam; and a control of forming a joint portion coupling the product and the offcut by running the second laser beam in an uncut region on the machining path, the joint portion having a thickness smaller than a thickness of the workpiece.